Possible acute coinfections in Thai malaria patients.

We conducted serodiagnostic testing for dengue virus infection, murine typhus, scrub typhus and leptospirosis in Plasmodium falciparum-infected individuals in Thailand. Sera from 194 malaria patients with a median age of 24 years were tested. No antibody titers diagnostic of dengue virus infection were demonstrated, but 29 (15%) of patients had serological evidence of scrub typhus, 45 (23.2 %) patients had evidence of murine typhus, and 15 (7.7%) sera tested positive for leptospirosis. Our serological results suggested that duel infections are not uncommon in malaria that is acquired in Thailand. However, our results must be confirmed by prospective studies aimed at describing the causative organisms. Mixed infections would have multiple implications for clinicians, including unexpected clinical findings and apparent poor responses to antimalarial treatment in patients thought only to have malaria.

Short report: detection of Orientia tsutsugamushi in clinical samples by quantitative real-time polymerase chain reaction.

Orientia tsutsugamushi infection causes scrub typhus, a common zoonosis of rural Asia. Orientia tsutsugamushi was recently detected by a real-time quantitative polymerase chain reaction (qPCR) assay in animal specimens. We evaluated the same qPCR assay in specimens obtained from patients with serologically proven scrub typhus infections. The 47-kDa qPCR assay was more sensitive than was mouse inoculation; it was reactive in whole blood specimens from all 10 isolate-positive patients and in 7 of 17 isolate-negative individuals (P = 0.003, Fisher's two-tailed exact test). As few as 1,076 O. tsutsugamushi copies/microL were detected in whole blood. Four of 7 sera from isolate-proven scrub typhus infections were also reactive by qPCR. The assay was unreactive in all 12 individuals without scrub typhus infection. This is the first demonstration of a sensitive and specific real-time qPCR assay for human scrub typhus infection.